24 Castle St, San Francisco, CA 94133

The two-unit residential building at 24 Castle Street in Telegraph Hill, owned by Clarence Lew and Pui Shan, has undergone several significant improvements since 2013, enhancing both its functionality and energy efficiency. The most substantial renovation work occurred in 2013-2014, focusing on the upper level with a comprehensive kitchen renovation and bathroom addition (approximately 165 sq ft), which included electrical upgrades (installation of 12 lights, 5 switches, multiple outlets, and new appliances) and plumbing fixtures (new sink, stove, bathroom facilities).

During this period, the building also received a major electrical service upgrade to 200 amps and the installation of energy-efficient windows, replacing four street-facing windows with double-hung wood windows featuring a U-factor less than 0.32. More recent improvements include the installation of a high-efficiency gas furnace (40,000 BTU, 95% efficiency) with new air ducts in 2016, demonstrating continued investment in the building's systems.

The most recent building permit on record from March 2015 indicates completion of previously approved work, with no outstanding permits or violations noted. The building, constructed in 1907 and classified as a Flats & Duplex structure, has maintained its residential classification throughout these improvements, all of which have been properly permitted and completed according to available records, with the exception of one expired permit from 2013 that was ultimately not pursued.